ASSO 99 Sail Configuration Guide

Overview

The ASSO 99 is a high-performance racing one-design conceived by Santarelli for competitive fleet racing. Its design philosophy emphasizes speed and agility, making it a favorite for inland lake racing and coastal regattas.

Rig Specifications & Performance Analysis

Analysis of the Santarelli rig dimensions reveals a highly efficient, modern sail plan:

• Mainsail Configuration: A P/E ratio of 2.71 indicates a high-aspect ratio rig, optimized for aerodynamic efficiency and lift.
• Foretriangle Design: The I/J ratio of 3.32 is exceptionally high, favoring tall, narrow headsails that excel in upwind pointing ability.
• Sail Area: 38m² of total upwind area provides a high power-to-weight ratio for the 9.96m hull.
• Performance: The configuration is strictly racing-oriented, requiring precise trim to harness the high-aspect sail plan.

Popular Sail Configurations

Due to the specialized nature of the fleet, configurations are often optimized for specific wind ranges:

• Mainsail: Typically a fully-battened high-aspect main to support the 11.25m luff.
• Headsail: Usually high-aspect ratio jibs that utilize the full 9.90m foretriangle height.

Key Characteristics

• High-aspect 2.71 P/E ratio ensures exceptional lift-to-drag efficiency.
• Tall 3.32 I/J ratio allows for narrow, weatherly sheeting angles.
• 9.96m LOA combined with a 2.93m beam provides a fast, responsive platform.
• High-performance design ensures the boat is close-winded and quick to plane.

Sailing Considerations

• The ASSO 99 is a technical boat requiring an active crew to manage the high-aspect rig.
• Optimal performance is found in light-to-moderate conditions where the tall rig excels.
• Precise backstay and halyard tension are critical for controlling the deep 11.25m mainsail luff.

Sailmaking Recommendations

For the ASSO 99, we recommend SurgeX membrane sails as the optimal choice for competitive performance. SurgeX utilizes continuous fiber construction where fibers are laid precisely along load paths and embedded in a thin membrane. This provides superior shape retention compared to traditional Dacron, which is essential for maintaining the aerodynamic efficiency of a 2.71 P/E high-aspect rig. The continuous fiber structure ensures the sail does not bag out over time, preserving the designed entry and exit profiles.

For racing applications, specify a lightweight SurgeX configuration with a carbon/technora fiber blend to minimize weight aloft and maximize acceleration. For those utilizing the ASSO 99 for performance daysailing, we recommend adding a lightweight taffeta protective layer on both sides to enhance UV resistance and durability against spreader chafe. Given the high-aspect dimensions, a tri-radial fiber layout within the membrane works best to handle the vertical loads of the 11.25m luff. A typical inventory includes a square-top or high-roach mainsail and a range of non-overlapping jibs. With 38m² of sail area, plan to reef or depower the main around 14–16 knots to maintain a flat heel angle.

Conclusion

The ASSO 99's high-aspect Santarelli rig is a masterclass in racing efficiency. Explore SurgeX membrane sail options for ASSO 99 to unlock its full podium potential.